ECG Alternans Detection via Template Subtraction and Feature Mapping

The patent applies preliminary action by performing template subtraction and noise filtering before alternans detection. The system pre-processes the ECG signal by subtracting a template beat from each detected beat to eliminate common artifacts and time shifts, then applies noise filtering algorithms before quantifying alternans patterns. This preliminary processing improves measurement precision by removing confounding factors that would otherwise mask the subtle alternans variations.

The patent uses an intermediary approach by introducing template beats as a reference medium between the raw ECG signal and the alternans measurement. The template subtraction process acts as an intermediary step that isolates the alternans component from the dominant QRS complex and other artifacts. This intermediary template-based approach enables more accurate detection of the subtle alternans patterns by comparing each beat against the established template.

The patent applies segmentation by dividing the ECG signal into individual beats and further segmenting each beat into morphological components (QRS complex, T-wave, ST segment). This segmentation allows the system to apply different processing strategies to different components, reducing overall complexity. By segmenting the analysis into beat-by-beat processing with template subtraction, the system achieves spectral-domain-level accuracy without requiring full spectral analysis of the entire signal, thus reducing computational complexity.

The patent employs partial action by applying spectral-like analysis only to the relevant portions of the signal (T-wave alternans) rather than performing complete spectral analysis on the entire ECG signal. The template subtraction method selectively processes only the variable components of each beat, achieving the necessary detection accuracy with reduced computational effort compared to full spectral domain methods.

The patent applies preliminary action by performing template-based alignment and subtraction before alternans quantification. The system pre-establishes a template beat and uses it to align and subtract from subsequent beats, eliminating time shift artifacts before measurement. This preliminary alignment step ensures that morphological variations are not confounded by temporal misalignment, achieving high measurement precision with relatively simple time-domain processing.

The patent uses copying by creating a template copy of a representative ECG beat and using this copy as a reference for comparison with subsequent beats. The template copying process preserves the morphological characteristics of the dominant beat while allowing subtraction to reveal the subtle alternans variations. This copying approach enables accurate time-domain alternans detection without requiring complex alignment algorithms.

The patent applies local quality by selectively applying template subtraction only to specific morphological components of the ECG signal where alternans is most prominent (primarily the T-wave region). The system preserves the full original signal for reference while applying the subtraction process locally to extract alternans information from relevant segments. This localized approach maintains measurement precision in the critical regions while minimizing information loss in other parts of the signal.

The patent uses the original ECG signal as an intermediary reference that is preserved alongside the template-subtracted signal. The system maintains both the processed (subtracted) and original signals, allowing verification and cross-validation. This intermediary reference ensures that no critical information is permanently lost, as the original signal remains available for comparison or re-analysis if needed.